Microsoft has not gone for the nuclear option with Windows 10 -- forcing the new operating system on consumers and small businesses now running older editions -- but it has tiptoed close to that line.

Five months ago, Computerworldlaid out the steps Microsoft had taken to distribute Windows 10, but noted that it had not yet moved to the next logical phase: not only downloading and initiating the upgrade, but completing it without any explicit user approval.

To recap, Microsoft kicked off the radical distribution strategy in January 2015 when executives announced that Windows 10 would be a free upgrade from Windows 7 and Windows 8.1 for one year after 10's official release.

The Redmond, Wash. company then moved on with a succession of schemes, including letting customers "reserve" a copy of the upgrade; downloading the upgrade bits in the background to those users' machines; and finally, in October 2015, saying it would automatically push the Windows 10 upgrade to all eligible PCs, then initiate the upgrade process.

That last step was to take place in two phases. First, the Windows 10 upgrade would be added to the Windows Update list on Windows 7 and 8.1 systems as an "optional" item. Next, Microsoft was to shift the Windows 10 upgrade to the "recommended" list. Updates on the latter are automatically downloaded and installed on most PCs.

Even then, Microsoft promised that customers would have the opportunity to cancel the upgrade once it began, and if they were unsatisfied, roll back the OS to the prior edition if they did so within 30 days of the upgrade.

Microsoft did, in fact, follow through with the two-step plan: It planted Windows 10 in Windows Update as an optional item no later than early February, and around March 12, began moving it to the recommended list.

But in March it also pre-scheduled the upgrade as it delivered the upgrade through Windows Update as a recommended download. According to a post by Microsoft Most Valuable Professional (MVP) Andre Da Costa -- who is not an employee of the firm but a moderator on several of the company's support forums -- Microsoft automatically scheduled the upgrade process to launch four days after the bits were downloaded.

And that's when Microsoft neared the nuclear option.

What is the nuclear option?

Even before Windows 10 launched -- since the appearance of GWX, the auto-installed app that initially let customers reserve the upgrade -- some cynical users wondered if the firm might dare to take the profound step of not only downloading and initiating the upgrade, but completing it without any approval.

Such a move would be unprecedented, not just for Microsoft and its increasingly-aggressive distribution strategy for Windows 10, but for the software industry historically: Upgrades have always been optional, even if passing came with caveats intended to motivate acceptance, such as dropped support.

The logic of a you-must-upgrade step was inescapable, as it was the inevitable end game of the year-and-more Windows 10 distribution strategy. And there were reasons why Microsoft might take that step, whether to simply add to the Windows 10 tally toward its goal of 1 billion by mid-2018, boost the number of systems eligible for apps or to better secure users' PCs.

Near-nuclear

Sometime in March, perhaps around the 12th, as Da Costa said, but no later than March 23, Microsoft changed how the GWX app and the scheduled upgrade worked.

Rather than interpret a click on the red "X" in the upper right as "cancel" or "ignore" the notification of the impending upgrade -- as decades of user experience (UX), as well as Microsoft's own design rules mandated -- the company defined the action as approval of the scheduled upgrade. Not surprisingly, the change riled users, who saw it as a trick to get them to approve the upgrade to Windows 10 when they intended to reject it.

Even with this behavior, Microsoft left users an out: Eagle-eyed customers could click on a link embedded in the word "here" in the notification to either reschedule or cancel the upgrade. But the machinations of the X-as-approval came very close to the line, using questionable means to get to the same ends as the nuclear option.

Call it "near-nuclear."

But users maintain that they were upgraded without their permission

Whether it's because they were duped by the red-X deception or paranoia-gone-amuck, some users have sworn that they didn't approve the upgrade to Windows 10.

"Computers at our medical practice are automatically upgrading to Windows 10 without permission and this is severely affecting our operation," contended Chris Leathart of New Zealand in one of many comments appended to a petition asking the Electronic Frontier Foundation (EFF) to investigate the practice.

"Microsoft installed Windows 10 on my system without my having any voice in the matter," asserted Louis Rourke of Massachusetts in another comment appended to the petition. "I could not even stop or interrupt the download. There was zero notice of how to refuse or undo this installation."

What's going on? Does the upgrade automatically kick off and complete if the PC is left unattended during the time when Microsoft pre-scheduled the upgrade?

No, said one expert, who argued that users were probably mistaken. Although they may have been misled, at the very least they had to have accepted the EULA (end-user license agreement), which serves as the defense of last resort for those who don't want to migrate. As part of the upgrade process, users are required to accept the Windows 10 EULA by clicking a button.

"I'm seeing reports all over the place that the installation has gone through without clicking 'Accept' on the EULA. But I don't believe it. I think people are clicking on Accept, not realizing what they're accepting," said Woody Leonhard, a contributor and columnist with Infoworld, which like Computerworld, is owned and operated by IDG. Leonhard has been extensively examining Windows 10's upgrade antics, including setting up numerous virtual machines with Windows 7 to track how the upgrade offer has been implemented.

"I've been able to recreate a couple of scenarios using virtual machines, but none of them end with an install," Leonhard said in an email reply to questions. "If the EULA sits there long enough [without a click on 'Accept'], it [the upgrade] finally fails."

Nuclear or not, the damage is done

In some ways, it does not matter that Microsoft stepped up to, but not across the line: The company has succeeded in alienating, antagonizing and angering portions of its customer base. Twitter hashtags like #upgradegate and #stopwindows10 have appeared, for example; discussion threads fill with accusations of unauthorized upgrades completing; and some make the dangerous recommendation to turn off Windows Update.

In a post-truth world, perception and repetition reign. But Microsoft has only itself to blame.

Woody Leonhard

This is the screen that appears when a Windows 10 pre-scheduled upgrade has not received approval of the software's end-user license agreement (EULA).